1/* re.c: This file contains the regular expression interface routines for
2   the ed line editor. */
3/*-
4 * Copyright (c) 1993 Andrew Moore, Talke Studio.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30#include "ed.h"
31
32const char *errmsg = "";
33
34/* get_compiled_pattern: return pointer to compiled pattern from command
35   buffer */
36pattern_t *
37get_compiled_pattern(void)
38{
39	static pattern_t *expr = NULL;
40	static char error[1024];
41
42	char *exprs;
43	char delimiter;
44	int n;
45
46	if ((delimiter = *ibufp) == ' ') {
47		errmsg = "invalid pattern delimiter";
48		return NULL;
49	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
50		if (!expr)
51			errmsg = "no previous pattern";
52		return expr;
53	} else if ((exprs = extract_pattern(delimiter)) == NULL)
54		return NULL;
55	/* buffer alloc'd && not reserved */
56	if (expr && !patlock)
57		regfree(expr);
58	else if ((expr = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
59		fprintf(stderr, "%s\n", strerror(errno));
60		errmsg = "out of memory";
61		return NULL;
62	}
63	patlock = 0;
64	if ((n = regcomp(expr, exprs, 0))) {
65		regerror(n, expr, error, sizeof error);
66		errmsg = error;
67		free(expr);
68		return expr = NULL;
69	}
70	return expr;
71}
72
73
74/* extract_pattern: copy a pattern string from the command buffer; return
75   pointer to the copy */
76char *
77extract_pattern(int delimiter)
78{
79	static char *lhbuf = NULL;	/* buffer */
80	static int lhbufsz = 0;		/* buffer size */
81
82	char *nd;
83	int len;
84
85	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
86		switch (*nd) {
87		default:
88			break;
89		case '[':
90			if ((nd = parse_char_class(nd + 1)) == NULL) {
91				errmsg = "unbalanced brackets ([])";
92				return NULL;
93			}
94			break;
95		case '\\':
96			if (*++nd == '\n') {
97				errmsg = "trailing backslash (\\)";
98				return NULL;
99			}
100			break;
101		}
102	len = nd - ibufp;
103	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
104	memcpy(lhbuf, ibufp, len);
105	lhbuf[len] = '\0';
106	ibufp = nd;
107	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
108}
109
110
111/* parse_char_class: expand a POSIX character class */
112char *
113parse_char_class(char *s)
114{
115	int c, d;
116
117	if (*s == '^')
118		s++;
119	if (*s == ']')
120		s++;
121	for (; *s != ']' && *s != '\n'; s++)
122		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
123			for (s++, c = *++s; *s != ']' || c != d; s++)
124				if ((c = *s) == '\n')
125					return NULL;
126	return  (*s == ']') ? s : NULL;
127}
128